<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <style>
    .box {
      background-color:red;
        /* inline:你可以和其他元素在同一行显示
            block:你可以设置宽度和高度
         */
      display: inline-block;

      width:200px;

      height:200px;
    }
  
  
  </style>
</head>
<body>
<a href="#">百度一下</a>
<div class="box">我是box元素</div>
<span>我是span元素</span>


</body>
</html>